OF SOUTH CAROLINA. 115 
mouth of Rocky River, on the Savannah. This, I suppose, is, next to Chester, in extent, as a 
locality of trap rock. 
Near the village a good opportunity occurs of studying the crystalline and basaltic rocks. 'The 
Court House stands upon granite, against which the metamorphic rocks are seen reposing to the 
North and South. A fine sienite, resembling the Quincy granite, is found here; and although no 
quarry has been opened in it, the masses on the surface give evidence of its great extent. Green- 
stone and hornblende rock are also found alternating with these rocks. Some remarkable dykes of 
Burite are also found near the village; and a few miles to the North-west they contain garnets. 
A curious variety of trap occurs here, that I have not observed elsewhere in the State. Its sur- 
face appears pitted, as if indented by a stone-cutter’s tool. This seems to be the result of a concre- 
tionary structure, or perhaps a tendency to crystallization: at all events, the small spheroids fall 
out, leaving the surface of the rock thus singularly marked. In the eastern corner of the District, 
between Barrattsville and Cambridge, trap abounds, and I have already mentioned that the village 
of Cambridge stands upon a series of trap and porphyritic rocks. 
Near White Hall, on Hard-labor Creek, there are several localities. Between the head waters of 
Wilson’s Creek and Long-cane, and again near the Double-bridges, on Rocky River, trap dykes 
come to the surface. 
The gneiss of Abbeville is also well developed; it may be seen in the beds of the rivers and 
creeks, particularly in the northern part of the District, where we find the western extremity of 
those thick strata that extend across the State, and give rise to the principal falls in the rivers.— 
One of the most southern exposures of the outcropping edges of this rock I saw on Long-cane, at 
Morton’s mill. The bands of black mica contrasting strongly with the feldspar, the folds and con- 
tortions of the lamin of this rock give it a very ornamental appearance. 
The falls at Ware’s mill, on the Saluda, are produced by the obstruction presented by the gneiss, 
as it crosses the Saluda. It occurs again on Rocky and Little River. So slight is the covering of 
slates in the northern portion of the District, that they are cut through down to the gneiss by every 
considerable stream. 
Mica and talcose slates occupy a considerable part of the surface of the District. After passing 
the ridge between Hard-labor Creek and Reedy-branch, we meet with a series of these slates, which 
extends nearly to the village, and through which Long-cane and its numerous tributary branches 
find an easy passage to the Savannah. 
Between McCord’s Creek and the Flat-woods, a strip of mica slates covers the surface, having 
Parson’s Mountain in the centre. 
This little knob is one of those elevated spots due to the comparative durability of the materials 
of which they are composed, and to which I have elsewhere alluded, as marking the comparative 
amount of denudation suffered by the surrounding strata. The direction of the crest of the moun- 
tain corresponds with the strike of the rocks, and on its very summit may be traced the ruins of 
an enormous stratum of quartz rock. In the north-eastern part of the District, particularly around 
Lowndesville, mica slate occurs, which passes gradually into a rock from which the mica has disap- 
peared, and which is there used for the manufacture of whetstones. There are other patches of these 
slates distributed over Abbeville, but they present little to entitle them to special notice, and the 
localities mentioned will be sufficient as examples of the occurrence of these rocks in the District. 
